I have a few core suggestions.

[u]Armor & Equipment[/u]
The CoH Enhancement system was unique in that it let players design their own skins, and then the enhancement system filled in their powers invisibly. This allowed players to customize their avatars to their own choosing, without being forced to use or wear items they did not want or like.

I propose that you implement a crafting system, where players can create items for other players. These items would be skins, as was done previously. You could make schematics for them drop from bosses and add them as rewards for the various achievements, etc.

[u]Ranged Tanking[/u]
DCUO showed us that tanking could be done from melee or ranged.

[u]Science Fiction[/u]
One of the great things about the CoH franchise was that it's roots were in modern times. It was not a rehash of so many fantasy games that many people have played. It was almost like the Anti-WoW, though I don't know that that was ever something that was done intentionally.

[u]Group Friendly[/u]
Another area where CoH was superior to many games. They encouraged you to group. Social interaction!

[u]Player Housing and Guild Halls[/u]
Instancing allowed for adding content without having to redesign maps. Designing maps with player housing and guild halls in mind would be a big step towards encouraging a player community and creating player driven content and interaction. We've seen that a strong community will support a game.